Process of detinning.



tinni'ng and is thereby Unrrnn STATES PATENT torsion.

CHARLES E. ACKER, or NIAGARA FALLS, NEW YORK PROCESS OF DETINNING'.

Specification of Letters Patent.

Patented'June 4t, 1 907.

' Application and Febrnary'5,1907- 8eric11o.365,840.

pressed scrap, however, are so narrow that' the reagent does not readily penetrate them and the speed of the reaction, is apt to be slow and the removal of tin incomplete. According to the present process, the reagent is subjected to increased ressure during dei hrced into the narrowest interstices of the scrap.

. In carrying out the process, the tin-scrap, mechanically compressed so as to occupy a relatively small. space, is treated in a reaction vessel, for example a steel drum or tank with a tight cover,'of sufficient size to con tain several tons of the material under treat-, The detinning reagent may be an ment. elementary gas or gas mixture, for example,

chlorin, bromin, or a mixture of either of these gases with other gases or air; a solution of an elementary gas in a li uid, for example, chlorin in carbon tetrach orid or stannic chlorid; or a gaseous orliquid compound, for example a chlorin compound in which the chlorin is loosely bound, such as bromin chlorid. Insome cases different portions of the bod r of scrap in the vessel may be simultaneously subjected to the action of a liquid and a gaseous reagept, the lower part of the vessel, only, containing a liquid in which the scrap is partially submerged.

During the detinning, the pressure in the vessel is raised, for example by pumping in chlorin. If a'gaseous reagent is employed, the air normally in the vessel will act as an inert diluent. It is preferred, however, to initially exhaust the air from the vessel con taining the compressed scrap. The reagent subjected to atmospheric or preferabl super atmospheric pressure, will then quick y penev trate all the interstices of the scrap. I a

When the scrap is com letely detinned, the gaseous or liquid pro nets of reaction are discharged, the pressure being decreased to or below atmospheric, and the residual metal is removed and is preferably washed,

in succession, with water and a dilute alkali solution, as usual in the art. In some cases the'pressure in the vessel is successively ,de'

creased and increased during the detinning andis then again decreased. For example, the vessel In'ay first be exhausted, the pressure' then increased'to or above atmospheric, and the final decrease of pressure efiected either by venting uper-atmospheric pressure or by again producing a partial vacuum within the vessel, such vacuum assisting the pemov al of the products of reaction.

I claim: c

V 1. The recess of detinning, which bdn sists in su jecting compressedtin scrap to the action of a detiiming reagent, and forcing the reagent into the interstices of the scrap by varying the pressure during the detinning.

2. The process ofdetinning, which con sists in subjecting compressed tin-scrap to the action of a detinning reagent, and forcing the reagent into the interstices of the scrap by pressure increased during the detinning.

3.- The rocess-of detinning, which consists in en jecting compressed tin-scrap to the action of a detinning reagent, and forcing the reagent into the interstices of the scrap by superatmospheric pressure.

4. The process of detinning, which consists in subjecting compressed tin-scrap in a closed vessel to .the action of .a detinning reagent, and increasing the pressure in the vessel during the detinning.v

5. The process of detinning, which con- 'Hg'em, successivelyv decreasing and increasing sists in subjeeting eempressed tin-scrap in e, I the pressure in the vessel during the detin- :0 closed vessel to the action of a (letinning rening, and again decreasing the pressure. agent, and suecessively decreasing and in- -In testimony whereof, I affix my signature .ereasing the pressure in the vessel during the in presence of two witnesses. detinning i w 1 1v 7 The process of detinning,' which eon- CHARLEb ALKPJR' s'is'ts in subjecting compressed tin-scrap in a nlesed vessel to the action of a (letinning re- Witnesses:

GEO. O. SEWARD, 1 GEO. *F. SEWARD. 

